private void QueryXml()
{
XPathDocument document = new XPathDocument("\\books.xml");
XPathNavigator navigator = document.CreateNavigator();

// Select all books authored by Robin
XPathNodeIterator nodes = navigator.Select("descendant::book [author/last-name='Robin']");
while (nodes.MoveNext())
{
Clone the navigator returned by the Current property.
// Use the cloned navigator to get the title element.
XPathNavigator clone = nodes.Current.Clone();
clone.MoveToFirstChild();

lblXml.Text = clone.Value;
}
}
}